This is an interesting modification on the question that I hadn't considered from how you presented it in the poll. I answered that it was learned, but could understand why it would be a question; the way you're putting it here, I think it is most certainly learned, and further that you have to reach a mental comprehension of why you should do this that goes against instinct.

What's interesting is that from a cognitive development standpoint we go through very distinct periods where we have zero empathy but expect 100% empathy -- literally the mind of a child below a certain age cannot perceive that their experiences are not shared by others. And then we go through another phase where we have cognitive realization of the fact that we don't share experience -- and then the lying starts. ;)

I think that true compassion is a very sophisticated thing, not at all natural to basic survivalist instincts.